Subject: Re: [PATCH iwl-net 2/2] i40e: take into account XDP Tx queues when stopping rings

From: Seth Forshee <[email-masked]>
Date: Thu, 1 Feb 2024 12:40:22 -0600

On Thu, Feb 01, 2024 at 04:42:19PM +0100, Maciej Fijalkowski wrote:
> Seth reported that on his side XDP traffic can not survive a round of
> down/up against i40e interface. Dmesg output was telling us that we were
> not able to disable the very first XDP ring. That was due to the fact
> that in i40e_vsi_stop_rings() in a pre-work that is done before calling
> i40e_vsi_wait_queues_disabled(), XDP Tx queues were not taken into the
> account.
> 
> To fix this, let us distinguish between Rx and Tx queue boundaries and
> take into the account XDP queues for Tx side.
> 
> Reported-by: Seth Forshee <[email-masked]>
> Closes: https://lore.kernel.org/netdev/ZbkE7Ep1N1Ou17sA@do-x1extreme/
> Fixes: 65662a8dcdd0 ("i40e: Fix logic of disabling queues")
> Signed-off-by: Maciej Fijalkowski <[email-masked]>

This fixes the issue we're seeing. Thanks!

Tested-by: Seth Forshee <[email-masked]>

> ---
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 2c46a5e7d222..907be56965f5 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -4926,21 +4926,22 @@ int i40e_vsi_start_rings(struct i40e_vsi *vsi)
>  void i40e_vsi_stop_rings(struct i40e_vsi *vsi)
>  {
>  	struct i40e_pf *pf = vsi->back;
> -	int pf_q, q_end;
> +	u32 pf_q, tx_q_end, rx_q_end;
>  
>  	/* When port TX is suspended, don't wait */
>  	if (test_bit(__I40E_PORT_SUSPENDED, vsi->back->state))
>  		return i40e_vsi_stop_rings_no_wait(vsi);
>  
> -	q_end = vsi->base_queue + vsi->num_queue_pairs;
> -	for (pf_q = vsi->base_queue; pf_q < q_end; pf_q++)
> -		i40e_pre_tx_queue_cfg(&pf->hw, (u32)pf_q, false);
> +	tx_q_end = vsi->alloc_queue_pairs * (i40e_enabled_xdp_vsi(vsi) ? 2 : 1);
> +	for (pf_q = vsi->base_queue; pf_q < tx_q_end; pf_q++)
> +		i40e_pre_tx_queue_cfg(&pf->hw, pf_q, false);
>  
> -	for (pf_q = vsi->base_queue; pf_q < q_end; pf_q++)
> +	rx_q_end = vsi->base_queue + vsi->num_queue_pairs;
> +	for (pf_q = vsi->base_queue; pf_q < rx_q_end; pf_q++)
>  		i40e_control_rx_q(pf, pf_q, false);
>  
>  	msleep(I40E_DISABLE_TX_GAP_MSEC);
> -	for (pf_q = vsi->base_queue; pf_q < q_end; pf_q++)
> +	for (pf_q = vsi->base_queue; pf_q < tx_q_end; pf_q++)
>  		wr32(&pf->hw, I40E_QTX_ENA(pf_q), 0);
>  
>  	i40e_vsi_wait_queues_disabled(vsi);
> -- 
> 2.34.1
>